Holley 600 dp jet help

Spring and screw on the accelerator arm adjusts the pump shot. Stock cams are usually pink and use #1 hole.
If it runs good with a 65 PV leave it as is for now. A 95 PV will add more fuel sooner.

If this is a used carb a previous owner could have changed the secondary linkage rod to open the secondaries faster. The primary should be open around 1/2 way before the secondary starts to open.